


Like Animals We Play Pretend

by an_aphorism



Category: Voltron: Legendary Defender
Genre: Alpha!Shiro, Alpha/Beta/Omega Dynamics, Anal Plug, Anal Sex, Breeding Kink, Dirty Talk, Dubious Consent, Filth, Just the Tip, M/M, Mating Bites, Mating Cycles/In Heat, Omega!Keith, Scenting, Teasing, afab language
Language: English
Status: Completed
Published: 2020-01-17
Updated: 2020-01-17
Packaged: 2021-02-27 09:33:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,778
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22294882
Author URL: https://archiveofourown.org/users/an_aphorism/pseuds/an_aphorism
Summary: Shiro shouldn’t have come. He’d known that every step to Keith’s door.But the Alpha instincts were strong. They were singing in his veins urging him just to go check. Just a quick little wellness check that everything was okay.His omega was in heat.Keith was /not/ his omega.
Relationships: Keith/Shiro (Voltron)
Comments: 115
Kudos: 1275





	Like Animals We Play Pretend

**Author's Note:**

> On the tags:  
> Dubcon throughout due to Keith's heat, but they're both hot for each other, and Keith is a active participant even if heat-hazed.  
> AFAB language, Keith's biology is pretty vague, but a few times Shiro does use AFAB language.  
> Breeding as kink is present in this fic. There's no mpreg, but Alpha Shiro does have a fantasy of it.

Shiro shouldn’t have come. He’d known that every step to Keith’s door.

But the Alpha instincts were strong. They were singing in his veins urging him just to go check. Just a quick little wellness check that everything was okay.

~~His omega was in heat.~~

Keith was _not_ his omega.

But Keith was in heat. He’d left the meeting abruptly, and the sweet smell that suffused the air as he went had told them all they needed to know. Hours later it was still stuck in Shiro’s head, that scent. As aromatic as it was intoxicating, he can smell the remnants of it now even outside Keith’s door.

He should just leave, but he finds he can't. Keith and he are friends, but that doesn't mean he should come knocking on an omega-and-in-heat's door. Especially when those friends that are Alphas.

But Shiro has to know that Keith’s okay. That he has everything he needs. That he doesn’t need—

He stops that thought and knocks. Nothing happens for a long time. Shiro knocks again, louder.

It takes a while, but eventually the door opens just a slit. Keith is there, mussed and red faced and openly surprised.

“Shiro?”

“Hey,” Shiro says, “I know you’re… busy.”

Scent pours out through the crack in the door and subconsciously Shiro leans in, propping one arm on the doorframe. Keith smells of cloves and fire and something burning. He smells good enough to eat. Shiro swallow hard.

“Yeah.”

“Just uh… needed to make sure you’re okay.”

Keith’s eyes are a little unfocused as he looks at Shiro’s bulging bicep and then at his face. “I’m… fine.”

“Okay,” Shiro can see just a sliver of him through the door. Keith’s wearing a long shirt that covers his modesty, but his feet are bare. Something about that twists a hot spine in his belly. “You just rushed out.”

“Yeah,” Keith switches his weight to the other foot. “You know how it is. Or uh, sorta.”

He means rut. Shiro swallows again, the saliva in his mouth increasing. The smell continues to waft toward him thick and heavy. Is Keith wearing anything under that shirt? The hem is close to Shiro’s hand, it would be barely be any effort at all to reach and—

He clears his throat, dragging his eyes back up. “Yeah,” they just keep saying that word, what does it even mean? “I uh, just wanted to make sure you have everything you need.”

Keith fidgets again and Shiro can see his nipples are peaked against the fabric. He bites his tongue.

“I have aids,” Keith says it soft, a little petulant.

Is it Shiro’s imagination or is Keith leaning in too? Was the door crack always that wide? Shiro moves in just slightly, drawn by how alluring Keith looks in the dim lighting. His hair is definitely sex rumpled, and it’s not hard to imagine exactly what he was doing before he came to the door.

But he needs to focus. Aids, Keith had said, he has heat aids.

They are common practice for both alphas and omegas, but everyone knows they hardly stand in for the real thing. Shiro knows first hand his own rut aids are… lacking. He’s never had an omega in heat because of how dangerous a game it is, but rut aids lack even the warmth and feel of a real person.

“Aids are… good.”

This gets a snort out of Keith. “They’re okay at best.”

“Yeah. Not quite like the real thing.”

“I wouldn’t know.” Keith looks down and his eyelashes are dark against his cheek.

Shiro clenches and unclenches his fist. “You’ve never…?”

Keith’s eyes flicker up. They’re a little blown out. "No,” he says.

Shiro can barely breathe through the smell of him. _Fuck_. “Not even for just scenting?”

Keith looks at his throat, tilting closer as though tempted to breathe Shiro in. Unconsciously, one of Shiro’s shoulders drop, an unspoken offering of his throat.

“No,” Keith’s voice is shaky.

Shiro’s blood is hot, the alpha in him too close to the surface. Later he will blame that for the words that come next.

“Ever wanted to?”

Keith bites his lip. They’re already too pink, like he’s had his teeth in them trying to stay quiet. Shiro wants to see them a well-kissed red.

“Sometimes,” Keith whispers it like a confession, mouth tilted up to Shiro.

They’re too close, the door hardly a barrier anymore. Keith’s radiating heat and scent, and Shiro’s other hand is itching to take. Everything about Keith is setting him off, giving him yes signals that his animal brain drinks in. He leans as far as he can then, nearly touching their foreheads together. They’re so close Shiro can feel the rough exhale from Keith.

“Invite me in,” he says.

Keith makes a sound like a animal caught in the trap, and his own hand falls away from door.

It slides open.

##

It’s something of a cat and mouse game then. Shiro stalks through the open doorway, metal hand casting it closed behind him. Keith retreats, walking backwards but keeping his dark eyes on Shiro. Keith’s den is drenched in heat scent, and it immediately starts doing a number on Shiro’s head. His eyes rove over those long legs, tease of Keith’s nipples against the fabric. The shirt is so short it just barely covers. Shiro’s cock is already more than half hard in his pants.

Keith walks back into the bedroom and Shiro follows. The tension is electric, and Shiro feels powerless to fight it. Keith looks like every wet dream all in one as he slides up onto the bed. His shirt rides up obscenely.

Beneath it there’s a hint of panties. Black ones.

Shiro has no idea then which of them is the cat and which of them is the mouse. He feels the hook in his own chest, pulling him toward the bed.

“Just scenting,” Keith says, half reclining on the bed.

Shiro’s eyes stay on Keith’s thighs and the black fabric visible to him as Keith's legs ever so slightly part.

“Yeah,” he says.

And then he’s standing at the edge of the bed. Below Keith is spread out against the rumpled sheets, an unbelievable fantasy. In his periphery he can see a tube of discarded lube and…

He turns his head, the colors drawing his attention. There’s an array of sex toys— _aids_. Heat aids. Some of them are still wet.

_Holy shit._

“Just scenting,” Shiro says. His voice is deep and strange. “Scenting,” he says again.

Keith’s chest heaves, “just to take the edge off.”

Keith’s bare foot is just beside Shiro’s hand. He could wrap his hands around the slender ankle and then slide up. He could part those gorgeous thighs and ~~lick~~ —

Scenting. They’re just scenting.

The smell of him is making it hard to focus. Shiro collapses down into the bed beside the omega and does not think about all those toys scattered on the other side of him.

Keith turns into him, propping his head up on one hand. “Are you okay to…? You don’t have to if it’s too much.”

Keith is fucking stunning like this, dressed down and relaxed. His eyes are a burn on Shiro, and even as Shiro knows he shouldn’t keep going, there’s nowhere he’d rather be. He can do this. He can control it. He’s a responsible alpha.

“It’s not too much,” he says. His hand comes up to tuck a wayward bit of hair behind one of Keith’s ears. “I want to. Help you.”

Keith’s smile is slight but devastating. He turns into Shiro's hand, nuzzling.

“Okay.”

The distance between them shrinks by degrees. They’re both cautious though, keeping their hips away from each other.

Still the shirt slides up naturally when Keith moves to tuck his knee between Shiro’s. Shiro’s hand is on his shoulder, and it’s a conscious effort to keep it there. From the corner of his eye he can just see the strip of black on Keith’s now uncovered hip.

It taunts him.

That’s not what he’s here for.

When they’re cocooned close enough Keith presses his face into Shiro’s neck. There he takes a deep, slow breath and then exhales. Shiro knows his own scent must be pouring off him, and the evidence comes a moment later when some of the nervy tension begins to leech out of Keith.

“You smell so good,” comes Keith’s muffled voice against his skin. “Fuck.”

A hot shiver runs down Shiro’s spine. His hand slips down to Keith’s arm and clenches. He’s throbbing in his pants now, cock hard and wanting. Everything in him is starting to tilt toward _omega, omega, omega_. It’s a natural, completely warranted reaction. Shiro has been brought into the nest of an in-heat omega, of course his alpha can only see one way this goes.

But it won’t.

Because they aren’t doing that.

Keith’s hands snake around his middle and he makes a high, omegan whine. Something in Shiro rumbles back.

“It’s so hot,” Keith says. His mouth smears over the gland on Shiro’s neck. He shifts against Shiro. ~~It’s a grind.~~ It’s not.

“You’re in heat,” Shiro says, so stupidly turned on.

There’s another sound from Keith, then clawed hands are plucking at Shiro’s shirt. Shiro hums and sides a hand up and down Keith’s back trying to soothe. It doesn’t work. Keith keeps tugging at the cloth making little disgruntled noises.

Shiro’s not dumb enough to misunderstand the intent, but he’s not about to do anything about it without Keith explicitly asking. There’s a lot of behaviors omegas can fall into in a heat and they don’t mean anythi—

“Off,” Keith’s teeth scale down his throat. “Now.” He jerks at the sleeve of Shiro’s shirt for clarification.

“Keith.” It’s a dangerous slide, even a little dazed already he can still see that.

“So hot, Shiro, _please_!” Keith couples the plea with a tender kiss to the underside of Shiro’s jaw.

And Shiro’s lost. He takes his hands off Keith, and they both drag the fabric up and over his head.

When Keith latches back on he does so with a croon of happiness. Shiro gathers him in, arms sliding around his slender middle. He feels and smells like heaven in Shiro’s arms.

That should be the end of it. Keith scents and nuzzles him, and it should be enough. They can just stay curled up here and ride out the end of Keith’s heat. Shiro will control himself, won’t give in to any of the urges pressing at him from beneath his skin.

A minute later Shiro knows his ideas about it being enough are nothing more than a pipe dream.

It’s a failure between them. Keith tugs and sucks and Shiro’s hands wander down to Keith’s lower back, playing with the hem of the shirt that has ridden up that far. The fabric is soft and thin and barely there. Keith’s nails scrape against Shiro’s sides, and Shiro’s returns it by scoring lines on Keith’s lower back. They pant and pull at each other in a slow breach of boundaries. Shiro should stop it, but he can’t.

He _wants_.

Then all of a sudden that careful distance between them is nearly gone. Shiro slides a thigh between Keith’s in a desperate last measure to keep him from grinding directly against Shiro’s cock.

It’s hardly better. Instead of pressing them hip to hip, Keith starts a slow rock against his thigh.

It’s _ruinous_.

“There ya go,” Shiro says, gruff. His fingertips are just at the band of Keith’s panties all of a sudden. He doesn’t know when that happened, only that if he moved just a little he could touch…

He tries to remind himself that this is for Keith. That they’re only scenting. It’s so hard with how good he feels, rubbing himself against Shiro.

There’s another whine as Keith’s rhythm starts picking up. The friction is utterly distracting, he can feel Keith hard against him. “Shiro— I— I can't—“

“It’s okay,” Shiro says. “I’ve got you.” There’s a wildness grasping him, and his hands slip down over Keith’s ass. “Just take what you need.”

Keith bites him hard then, grinding filthy against his thigh. Shiro’s hands clench on the swell of his ass, the silky fabric of panties sliding beneath his palms. He helps Keith’s rhythm, guiding him steady.

But he can’t stop thinking about the panties. He wants to tear them off so badly and shove his fingers into that leaking, tight cunt until his omega comes. He wants to just pull them aside and bury his cock into that heat. He wants to do so many things to the teasing omega showing off for him.

“Please,” Keith gasps. He pushes into Shiro’s thigh, and then pulls back and forces Shiro to hold him tight. The scent of him is suffocating now. His hole must be dripping, the flimsy silk doing little to contain it. “The aid,” Keith says, like a request.

That’s a difficult thing to think about then. Shiro’s mind is slow and stuck on the lush curves of Keith under hand, the easy slip of his panties as they’re worked lower with his rocking. Shiro needs to unbutton his jeans. He needs ~~to get his cock—~~

“The aid?” He swallows the saliva, his heart a thunder.

Keith interrupts his own rhythm then and Shiro’s hands are suddenly on the bottom of his ass, slipping through wetness smeared all over.

“The aid,” Keith says meaningfully.

Shiro’s mind spins. Keith’s a mess down here, drenched and sticky. It’s so fucking hot Shiro can’t cope. His fingers slide around the wetness, not touching Keith where it’s coming from, but just playing with the excess. The aid, he’d said. As in heat aids. They've talked about this. _Head aid_ , Shiro's mind focuses slowly, _as in something that’s already inside Keith…?_

Because of course there is. Keith’s in heat and had been taking care of himself before Shiro arrived. Of course he’d have an aid in. The idea is a doozy. There was something already inside Keith's dripping hole. A nice, cock shaped something that Keith had been clenching around during his heat.

The thought of it there instead of his own knot has a growl rise out of Shiro’s chest. It sound like a rock slide, deep and terrifying. Before the omega can react, Shiro pushes Keith onto his back. He follows, pressing them together more completely, settling himself between Keith’s thighs.

“Fuck you’re so hot like this,” to avoid his lips, Shiro buried himself in Keith’s neck, breathing in the spiced smell of him. “Can you feel me? How hard you’ve got me?” They’re alpha words, hard and dark and spun right into his omega’s ear.

Keith moans, clutching him tighter, winding his arms and legs around him.

“We can’t,” Keith whines.

Shiro grinds against him, nipping his throat. “I know,” every breath is a heaving effort, “I know. You’re just— I bet you’d feel amazing, you’ve already soaked the sheets you’re so wet.”

Keith arches and cries out. Shiro’s hands are braced to keep him from crushing Keith, but he yearns to put a few fingers in that mouth and make Keith moan and suck on them while he fucks him.

Except, they’re not fucking. _Not._

They’re just—

He grinds against Keith again, a slow and filthy push that has them both gasping for breath.

“Need…” Keith huffs. Then his hands unwind and he’s pushing at Shiro’s chest.

Shiro pulls back, but before the confusion can bloom, Keith is rolling over and presenting.

And for the first time, Shiro gets a good look at him. On his belly Keith’s shirt is still rucked up and those silky panties are pulled ever so slightly down on one hip, as though begging to be removed. His ass is full, and an absolute dream. Shiro’s been staring at it in tight Blade suits and yoga pants, but it’s another thing altogether to see it almost bare, just a tight strip of damp silk to contain his modesty.

Keith’s hips tilt up and the smell is—

Shiro collapses back against him, hips now pressing against his ass, rubbing against that scent and slick.

“Yeah just… just this. Okay?”

Shiro would agree to anything at this point. He has Keith under him, dripping in heat and presented. It’s all for him. ~~Just for him. His omega.~~

He buries his face against Keith’s shoulder blade. “Yeah,” he growls, thrusting against Keith’s ass. “Yeah.”

At that first hard thrust Keith mewls and presses back into him. Shiro remembers the heat aid. The heat aid that’s in Keith. The heat aid that with every rocking thrust Shiro makes will push deeper into him.

It’s not strictly fucking, but the idea just destroys him. Shiro’s hands clamp over his omegas hips, and the next thrust is almost punishing, aiming to scrape just where the plug would be.

Keith yowls and shreds the bedding. “Alpha!” He cries. It’s an unforgettable sound. 

So Shiro does it again. And again. He thrusts against Keith’s as though it were his own cock in that sweet wetness. He grinds into him as if working Keith down onto his knot. Keith would be so good around him, so tight…

It’s agony. Jeans are the absolute wrong material for both of them. Shiro’s cock is pinched and throbbing, and after only a few thrusts the pale skin of Keith’s ass is getting pinkened from the rub.

“Keith,” he groans pressing close again and shifting his hips. “I need— these jeans. Wanna feel you. Just, just like this.”

Keith pants into the bedding, flushed and so ready to be mounted. ~~Ready to be bred~~ —

 _No_.

“ _Yes_ ,” Keith says.

The single syllable nearly breaks Shiro. Then the last of his higher brain function kicks in. Keith isn’t saying yes to breeding, he’s saying yes to jeans. To Shiro taking them off.

Shiro’s fumbles up and strips, casting aside the clothing with mindless efficiency. He’s never removed jeans so quickly. When he descends back into the bed he’s only in his boxers, his cock pressing hard against the material. It doesn’t help to get another look at Keith’s ass, which is still raised. His panties are clearly soaked now.

“Fuck,” Shiro grates as they slide back together. It’s an sensation that gets all his nerves trembling, and twists the alpha thing in his head. The scent of Keith is all over, and the wetness seeps into Shiro’s boxers as he thrusts his cock back against Keith’s ass.

His hands find Keith’s wrists and pin them down.

“Fuck,” he growls into Keith’s ear.

The omega makes an approving, wanting sound. It’s delicious. He licks the stretch of Keith’s throat, luxuriating in the salty taste of him.

“You’re—“ Keith whines again as Shiro’s cock sides against his hole. “Big. _Stars_.”

The alpha in him preens at that. “Can you feel that?” There’s still two very thin layers of cloth between them, but the slick is doing a lot to make it feel as though there isn’t. “You’ve got me so hard baby. The way you sound, the way you _smell_ …”

Keith’s hips press back, meeting the next thrust. “Need,” Keith says.

Shiro’s hands tighten around delicate wrists. “What do you need?”

Keith head turns and his eyes are Galra bright, completely lost. His eyelashes flutter and the one eye opens to look at Shiro. Shiro presses against his dripping cunt and holds, cock throbbing to be _inside_.

“Alpha,” Keith whispers. “I need your knot.”

Shiro tears his gaze away, biting fiercely at Keith’s shoulder. The need rises in him until he can’t even think through it. His omega wants him, needs him.

“Just…” He takes his teeth out of Keith’s skin and kisses the bite. “Just a little more, I won’t— we won’t—“

His hand is sweaty when he lets go of one of Keith’s wrists and reaches down for the panties. The omega croons and tips his hips just a little bit more up as Shiro hooks a finger into the fabric and tugs.

He can’t get himself to move away, so he just tugs the silk down as far as they’ll go with Keith’s legs spread. Then he reaches for the band of his own boxers.

He can’t look. His heart is a gallop and the pleasure in his veins is so loud he can barely hear anything else. The fabric is sticky to pull off his cock. It’s impossible to know how much of it is his own precome and how much is Keith’s. He pushes them down his own thighs and doesn't bother with anything further.

Completely bare, Shiro settles his cock right into the crack of Keith’s ass. He doesn’t look, just does it just by feel. It’s more than enough.

Skin to skin is like a nothing else. They’re both burning hot, and Keith’s whole backside is slick. The need has them drawn tight together, holding on to the fraying edges of sanity with claw tips.

At the first thrust between Keith’s cheeks, there’s an obscene sound. Keith moans.

“Better?” Shiro doesn’t recognize his own voice. There’s a hard clip to it. He’s hyper-aware though of his cock against the end of the plug now. It’s a subtle thing, but he rubs himself just to push it in, to play at fucking this gorgeous omega. “Yeah. How good you take it. Just dripping. You need more baby?”

Keith makes a sound of assent.

“You need a proper knot, don’t you? Hungry little thing like you. Always want more and more. You ever taken a cock this big?”

Shiro’s bent over him, whispering the words right into the omega's ear. The man beneath him squirms while listening.

“No,” Keith says. Shiro can see his cheeks are dark flushed, eyes closed. His nails are longer than they should be against the bedding. “Never that big. Never knotted. Properly. Shiro—!”

Shiro fucks against him, building the rhythm again, but this time skin to skin. His hand skirts around Keith’s hip and under, touching the flat planes of his belly.

“Bet if I fucked you I could feel it here,” Shiro’s hand dips and then stops just shy of Keith’s cock. “You’d be stuffed full of me.”

Keith curses. “I want it... want it.”

Shiro sucks a bruise into his omega's throat. “Me too. But we can’t, remember? You’re in heat.”

Still he drags his nails through the pelt of hair just above Keith’s cock, and then over the top thigh crease. Keith makes a hot, caught sound and his hips dip more in offering.

The next thrust has Shiro’s cockhead sliding over the plug at an angle that tears something down inside him. He feels dangerous, possessive.

“We could,” comes Keith’s strangled voice. “Just a little… just to know how it feels.”

Shiro layers kisses down his neck and shoulder. Keith tastes like the finest desert, sweaty and spicy. _His_.

“You want to know what this would feel like?” Shiro tilts back just a little and takes his hand to his own cock. He taps it gently against the skin of Keith’s ass. The sound is heavy. Filthy.

Shiro can’t help himself, he looks down.

Keith’s ass is a spectacular vision. It’s a plush swell, pinked from the thrusting, and smeared wet. Shiro’s cock is sitting just near the hole, looking too big to fit. That idea makes him _throb_.

And then there's the heat aid. Knowing of it is completely different from finally seeing it, and Shiro takes a moment to just stare. Only the end of it is visible, a little red thing keeping his hole nice and plugged. The alpha in Shiro rears up, covetous of the prize in his hands.

“Look at you sweetheart,” Shiro’s metal hand comes down on Keith’s back, pushing gently. “Bend for me, let me get a good look.”

Keith does easily, and Shiro doesn’t miss how his hole clenches around the plug.

“Fuck you look so good.”

Keith garbles his name with a breath of air.

“Yeah,” his cock is there then, bumping the plug, sliding through the slick that’s still weeping out. “Want something a little thicker, hm? Would fuck you so good, knot you deep and breed you.”

His thumb joins as well, pulling at Keith’s rim just to watch it pulse and clench. He can practically feel that around his cock, working him to spill.

“Breed me,” Keith says. “Please, I need it. _Alpha_.”

Shiro’s mind has left him almost completely. He’s burning up in a daze, touching Keith here, sliding finger and cock around that needy hole.

Then he presses down on the plug.

The cry from Keith is sharp and wanting. “Take it out,” Keith demands when he catches his breath.

Shiro doesn’t think about it, he just does what his omega says. His fingers grasp the end of the plug and start to pull.

Keith wriggles and mewls when it’s removed, and Shiro doesn’t even breathe. The plug is deceptively large and absolutely dripping as he inches it out. Shiro’s never seen something so obscene in his whole life. It comes out and out, so long that the doubts about Shiro fitting dissolve immediately.

And then the plug is completely out, and Keith’s messy cunt is presented to him, ready.

There’s a bead of precome on Shiro’s cock so close that should it drip, it would fall right into Keith’s hole. He imagines it so clearly, a pearlescent bit of fluid against that rosy rim. He could put his finger to it and just push it in.

The aid drops somewhere with a clatter, but Shiro doesn’t care. He can’t take his eyes off the omega’s offered ass. Better than a finger, Shiro thinks, would be his cock. With as needy as the omega is, Shiro would just slip inside. He could fill Keith up, give him what he really needs. There's barely an inch between them, it would be so easy.

As if hearing his thoughts, Keith pushes back.

Then Shiro’s cockhead is just against that hungry cunt.

“You just want to be teased, don’t you?” Shiro moves the head around Keith’s rim. “You know we can’t do this, but you just can’t help yourself.”

“We could… just a little.”

Shiro hums, catching the rim and then letting it slip past. His cock slides pleasantly between Keith’s ass cheeks. It looks so good there, thick and dark red against all that delicate, pale skin.

“You think you could? Just let me push a little in and then stop?” The idea is infiltrating him, and Shiro leans into it. “I could. I’d let you warm my cock. Use you to jerk off until I pulled out and spilled on your ass.” He laughs low and dark. “Or maybe I should just spin you around and shove this down your throat. Let you gag on it until I come. Would that be enough of a tease baby?”

“Alpha!”

Shiro’s hands settle hard on his ass, pulling him apart until his hole gapes a little. With careful aim he slides his cock against it, just missing the angle that would sink him into that heat. “What do you think?”

“Please!” Keith sounds agonized, his hips shifting as though he could find the right angle. “Just a little. A little and I’ll be so good. Fuck. I need— I need it.”

Shiro would be lying if he said he wasn’t in the same dire straights. This all has gone on long enough that his cock is a constant throbbing need. The solution is just there, begging him for it and—

“Just a little,” Shiro swallows hard. “And you’ll be good for me.”

There’s a quiver in Keith then. “So good, so good. Just need a little, just need—“

His mind is a fog. Shiro couldn’t even begin to shake it off. His cockhead is swollen and shiny and just at Keith’s hole. His omega is begging him.

 _Just a little_ , he said.

And who is Shiro to deny him?

He pushes the fat head in.

Immediately the sensation is so good that Shiro sinks in a bit deeper. Beneath him Keith moans, throaty and full. Around his cock the wet, blazing heat clutches at him.

It’s fucking _amazing_. Shiro buries his head against Keith’s throat, smothering himself in the omegas scent. He smells of unmated omega, _his omega_. He needs to fix that.

“How’s that feel?” Shiro growls. He’s barely in past the head, but Keith’s fluttering around him like he's close. It's _sublime_.

“So good, fuck, you’re so— stars, alpha, _alpha_!”

“Yeah,” Shiro pushes in a little more than he should, and then forces himself to pull out. Keith’s cunt practically sucks at him to keep him in. It’s unbelievable. “Still so tight. So perfect. Been keeping this from me all this time, but you need it. Need a fat cock in your pretty hole.”

Keith pushes back again, and his cock slides back in. It’s little more than the head, just as they agreed.

Bliss and torture. Shiro can feel how Keith suffers too, his body tight as a bow beneath Shiro.

“ _More,_ ” it's a demand.

Shiro’s cock pushes in just a sliver before he can stop. His teeth drag against Keith’s skin. “We can’t.”

Keith makes a mournful chirp. “We can’t," it sounds less like an agreement and more like a damnation.

They go on like that a while. Shiro fucks just the tip in, luxuriating in the tight squeeze of Keith’s rim around the corona. He know he’s leaking a mess, leaking _into Keith_ , but he can’t stop. It’s the most exquisite pleasure and agony.

And then Keith pushes back on a thrust, and Shiro’s cock sinks deeper.

“Keith!”

But Keith can’t hear him over the quavering cry he gives as Shiro’s cock slips over that spot inside him. “ _Please_ ,” Keith begs, “Just a little. I’m close—so— alpha please— I need— you feel so big, so good— “

There’s no strength in Shiro left, not with a delicious omega like this. He grunts and pulls out only to push back in deep. “Just a little,” he agrees, but even as he says it he can feel those words slipping away from him. Keith’s hot and perfect on his cock and already his knot has started swelling. The heat scent and hot cunt wrapped around him is more than enough to make his alpha brain think about knotting. He pushes deep and stops just short of the knot.

Keith cries out.

Shiro does it again.

It’s a slow, molten fuck between them. Shiro tries not to escalate, but Keith keeps pushing back, forcing Shiro’s cock back inside him dangerously deep. 

Shiro sucks another bruise on Keith’s ruined throat. “Baby you’re taking it so good, too good. Can’t— much longer. I need to stop—“

Keith shakes his head against the sheets. “Just… a little more.”

Shiro could reach around and jerk him off, let his omega get a much-needed orgasm, but he wants him to come like this, on Shiro's cock. There’s something about that idea that has stuck in the back of his head, feeding his alpha possessiveness. He knows he can get Keith to come like this if he just… a little more.

And then he’ll stop.

He’ll pull out, and they won’t—

The fuck is so slick. Shiro’s rhythm picks up, driving him deep and hard right against Keith’s spot. It’s enrapturing. Keith’s clenching now on every push in, making tiny needy sounds as his body tightens and Shiro drives him closer to the end. His knot is fully formed now, bumping the outside of Keith’s cunt every time. The temptation is all-encompassing, and he bites and sucks his omegas neck, his own whine pressing blurry against the skin.

“Alpha,” the omega's hips tilt, a perfect angle to press in that extra bit.

“ _Want to_ ,” Shiro moans. It wouldn’t take anything to press a little bit more. “You’d take my knot. Take it perfect. Let me breed you, omega. My omega. _Mine_.”

“ _Yes_ ,” Keith says. He sounds as out of his head as Shiro is. The fucking is hard now, too fast and deep to be anything even slightly resembling _little._

But Shiro doesn’t want to stop. He wants to have his omega completely. He wants to spill hot into his cunt, give him pups. He wants to breed him so everyone will know that Keith is _his._

“Yours. Alpha, give me your knot. I _need— need—_!”

There’s a strange, wavering cry then. An omega cry. The cry of one who needs desperately to be bred.

Shiro’s mind shatters in a hundred directions beneath the sound. He’s supposed to stop, to pull out, but he can’t remember why. It feels amazing, _right_ , and it doesn’t make any sense to stop. He’s going to take this omega, take _his_ omega just as he’s begging to be taken.

Shiro’s hands dig into the perfect curves of his omega's hips, and pull him back hard on his cock. There’s a moment of pressure and then his knot sinks in. Instantly the omega shrieks and begins to come.

There’s not much left to Shiro’s stamina, so he ruts himself in that pulsing cunt, driven by the pleasure and possessiveness. His teeth lock down on the scent gland of his omega's throat, and he snarls through the impossible pleasure that is peaking inside him.

When he comes, it’s with his knot buried deep, the knowledge of his spill deep inside his omega’s womb spiking through his veins. It’s never been better.

He comes for what feels like ages. The pleasure is thick and heady and he fucks the little amount he can, getting his seed that much deeper. His omega is going to be stuffed, dripping for _days_ after this. The pride wraps itself in his pleasure and makes it sweeter.

And then the tide begins to recede. They collapse, slowly, into the sheets with Shiro’s knot tying them together. For the first time ever, the alpha in him feels completely satisfied. He’s warm and snug inside his gorgeous omega. He could sleep like this, plugged tight to make sure it takes.

 _Wait_.

Shiro's lungs are heaving, but with every breath the haze begins to lift. Thoughts and ideas and words come back to him. He realizes, with equal parts pleasure and horror, what’s happened.

Beneath him Keith shifts. He's slick in sweat and come, his cheeks a ruddy pink. “Oh fuck,” Keith says. His voice is ruined.

Shiro's eyes track to the unmistakable bite on Keith’s throat. The mate bite.

“ _Oh fuck_ ,” Shiro parrots.

**Author's Note:**

> And then they have an awkward 'oops that was definitely NOT just scenting' talk, and shyly kiss. Shiro asks him out on a proper date. 
> 
> This idea was inspired by twitter users @aNEM0nefish, who wished there was more 'just the tip' stories, and @slouph_art who is making spicy ABO friends with scenting benefits art that I am obsessed with. Both will be linked on my twitter for those interested!
> 
> Comments get me through grad school. 
> 
> I'm @an_aphorism on twitter, where I post problematic filth about hot fictional men.


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